Category Archives: 101 diagram

Looks pretty good…. Two completely different computer models show tropical moisture getting into Arizona in about 5-6 days a resulting preview of the summer rain season. You can find quite a bit of “green pixies” (areas of rain denoted by areas of green pixels) in Arizona here from IPS Meteostar’s rendition of our best model, the WRF-GFS. And, the Smoking Canadians have rain in our area in their model, too. This is going to be the best chance for measurable rain in Catalina since early April!

In the US model linked to above, you can also see the residual low pressure center from today’s Hurricane “Crissy” moving up the coast of Baja Cal in five days. Finally, could we have a month with above normal rain after not having one since November 2013 (or was it 2012?) Might happen, after all we deserve it. So, I will now predict that June will be above normal in rain in Catalina, AZ.

You can keep track of Crissy here. I will be tracking Crissy, that’s for sure.

Below, an example of rain (with drizzle) in case you’ve forgotten what it looks like in a research aircraft with laser beam imagery of all the stuff you’re flying through:

Rain (and drizzle drops) as seen by aircraft instrumentation, arranged in order of small to larger, left to right. The horizontal lines are just about a millimeter apart, so the biggest drops here, one that aren’t breaking up, are about two millimeters in diameter. Drizzle drops, as CMJs know, are those between 0.2 to 0.5 millimeters in diameter, so there are a lot of those. BTW, these were collected while the aircraft was flying at about 160 knots (80 meters per second). Pretty amazing you can image these drops as they go by so fast!

The discerning reader will want to know what spaghetti sez; what are the chances that the steering winds in the middle of the troposphere will steer Crissy toward us as it moves around off’n Mexico. Will those steering winds help Crissy’s moisture get into Arizona and over Catalina?

We seek help from spaghetti and, indeed, the spaghetti shown below is “supportive”, that is, it shows that the “planets are lining up” for rain here, as an astrologer might say, those people we look to for personal guidance in everyday matters; whose forecasts are so important no newspaper can go without them without causing an uproar on the part of their readers.

See writing on figure below for some additional weather interpretation.

Valid for 5 PM AST June 16th. Those red lines suggest that Crissy’s remains (RIP) might indeed be directed at eastern Arizona! Big trough for this time of year foretold along West Coast with high confidence, as indicated by “bunching lines”, perfect for drawing tropical storms northward into the Southwest US. If not us, then those dry areas of New Mexico and west Texas virtually guaranteed for some tropical air.

Yesterday’s clouds

10:53 AM. Mostly Cirrus uncinus, bisected by a contrail.2:38 PM. Cumulus humilis and fractus boiled up out of 100 F plus air at the surface.Tops warmer than -10 C, so no ice, just those thin patches of Cirrus on top.3:08 PM. Cirrocumulus atop Cumulus fractus clouds.

Nice Altocumulus around this morning, but moisture is really confined to that level, not deep enough for rain at the ground. The Cumulus that form this afternoon will have bases around 14,000 to 15,000 feet above the ground. They should be deeper than yesterday, and so ice is likely to form in the larger ones (and we hope that you will log that in your daily cloud diary), but only tantalizing virga is likely, maybe with some brief windy periods near them.

I’m not missing any of this. Its too good. Supposed to rain off and off until the frontal blast about 10 AM -Noon, then clear up for awhile, then scattered showers develop from what will be icy looking Cumulus and small Cumulonimbus clouds, kind of the usual storm chronology we have here. This sequence shown in the U of AZ model run from last night is here, and its been well-predicted by the media weather folk as well. Don’t watch TEEVEE much, but I did catch some bits and pieces by George. It was pretty comprehensive, quite good really, and then I started to feel sad. Why am I doing this, blogging about weather myself when its already out there???????????????????????? Oh, well.

It will be interesting to see if there is more than a few flakes of snow as the front goes by, the rain becomes moderate to briefly heavy, and that’s when the precip will start to have ice in it, maybe turn to snow for awhile due to a diabatic effect where the snow level comes down due to big melting snowflakes dragging it down. An early morning frontal passage would have been better for the best snow accumulation, but, oh, well.

Still looks to be an appreciable amount here, both eyeballing the situation and in the U of AZ mod run from last evening. From this keyboard yesterday, the best estimate for this storm that just kind of popped out was 0.450 inches (the median between a lower limit of 0.20 and upper one of 0.70 inches). Since “we” last wrote, the U of AZ model has increased its precip for us, as though it was affected by something I said. The green “half inch” region has crept that bit closer to Catalina in this latest run below over where it was yesterday.

Accumulated precip for the 24 h ending at midnight tonight.

And we’ll need as much rain as we can squeeze out of this one as the follow up series of storms foretold so long ago in the mods have disappeared–shown during a time when our “truth viewer”, those NOAA spaghetti plots were down for a few days, or they might have tipped us off to be more “circumspect” about a run of storms by showing that they were not reliable predictions. No further rain is forecast for the two weeks after this now! Dang!

The intermittent rain that has been falling is WAY ahead of the front, over there by Yuma as I write at 4:41 AM.

Its developing in the moist flood of air that rushed in overnight at lower levels along with a huge icy shield overhead, no doubt a thick Altostratus with virga on top of Stratocu, maybe dumping some drops into the lower cloud deck. Need more of that.

——————Learning module———————–

The effect of rain drops falling into a lower layer of Stratocu?

If you dropped a cup of water on the top of the layer yourself, the amount coming out the bottom would be more than a cup. Those fast falling drops, about 5-10 meters per second, say for regular raindrops, collide with the itty bitty cloud droplets blowing sideways in the wind. The larger cloud droplets, say bigger than 20 microns in diameter, collide and stick to the fast-falling raindrop, adding to its size. We call this accretion. That bottom kilometer of storms where otherwise “harmless”, non-precipitating Stratocu is likely to be, is critical for appreciable snow and rainfall due to this process in mountainous regions. Almost always, the impression is that its the Stratocu that’s precipitating, but usually its not. So, when you see a raindrop fall, thank a Stratocu deck for making it that bit bigger, thought in some cases to increase precip by 50% due to the effect of accretion in the bottom kilometer (3300 feet).

Might look like this if you could step back to the south of the Catalinas today and draw a crummy cartoon of what was happening, but it was the best you could do at the time

From a 101 class I taught at the U of WA, with modifications to show I am in Catalina, AZ. Background: couldn’t get the real guy to teach that class that summer, and so I was enlisted to do the job at the last minute, thus lowering the accreditation rating of the University of Washington. You see, I have NO ADVANCED degree of any kind, and to have a lecturer without the big Ph. D. means you go DOWN! On the other hand, unlike most faculty at ANY university, I have been asked my opinion on something and was quoted about it in the Wall Street Journal in 2011! Oh, yeah, baby! Wanna spike a football right now! Credentialism; a bunch of hooey (sometimes).

————end of learning module and statement on credentialism aloong with a display of immaturity—————

Back to the storm…. After a couple of light and brief showers, we have amassed 0.01 inches! Only 0.44 inches to go to make a perfect prediction!

Yesterday’s clouds

Kind of a bust, really, and admitting that will make up for some exultations above. Sure, there were some Altocumulus with virga hanging down, but those virga trails needed to be about 20,000 feet longer to be anywhere near where I thought they would be. And then it cleared off almost completely during the afternoon! Oh, well. Pretty day, with lots of wind and mild temperatures. Here are a few shots:

6:55 AM. Altocumulus floccus virgae–has virga. These were up around 20,000 feet above sea level, or about 17,000 feet above ground level here in Catland. Top temperatures with all that ice falling out? About -26 C (-15 F).7:12 AM. Ditto.9:46 AM. More of the same but less.

6:25 PM. After a clear afternoon, a vast shield of Altostratus/Cirrus advances on Catalina.